1. Field of the Invention
This invention relates to an electrode forming apparatus for electric parts, in particular, to an electrode forming apparatus that can easily form electrodes on board-shaped electric parts in turn by conveying the board-shaped electric parts with their attitudes kept fixed.
2. Description of the Related Art
In the prior art, electric parts are conveyed by a conveying tape that is intermittently moved.
When electrodes have to be provided on the electric parts, the electric parts are sent to an electrode forming apparatus. The electric forming apparatus carries out a predetermined electrode-forming operation to the electric parts.
In order to improve the efficiency of the electrode-forming operation, it is preferable that the electrode-forming operation is carried out to the electric parts remaining held by the conveying tape, that is, without being removed from the conveying tape.
Inventors of the present invention have developed a conveying tape 90 as shown in FIGS. 11A and 11B, previous to the present invention. FIG. 11A shows a plan view of the conveying tape 90 and FIG. 11B shows a cross section view taken along bxe2x80x94b line of the FIG. 11A.
As shown in FIGS. 11A and 11B, the conveying tape 90 consists of a conveying tape body 91, a plurality of work holders 92 attached to the conveying tape body 91, and a plurality of feeding holes 93 formed in the conveying tape body 91. The conveying tape body 91 is made of a material hard to stretch, in order to assure highly accurate positioning thereof. However, the work holder 92 are made of elastic rubber, in order to stably hold electric parts 94 as works.
The above conveying tape 90 can hold and convey the electric part 94 as the works stably. However, because of the elasticity of the work holders 92, the electric parts 94 held by the conveying tape 90 may move away from their desired positions when electric conductive paste is directly applied thereto. Therefore, it is difficult that the electric conductive paste is applied to predetermined areas of the electric parts 94.
Inventors of the present invention have conducted many examinations and investigations. Then, they have found that a mechanism for sandwiching the electric parts 94 from both sides thereof can give substantially the same pressing force to the both sides in order to prevent the electric parts 94 from moving away from their desired positions.
However, in the conveying tape 90 described above, it is difficult to form thinner work holders 92. Thus, as shown in FIG. 11B, both ends of an electric part 94 (a work) may not protrude from both sides of a work holder 92 when the electric part 94 is low (the work is small).
The object of this invention is to solve the above problems, that is, to provide an electrode forming apparatus that can easily form electrodes on board-shaped electric parts in turn by conveying the board-like electric parts with their attitudes kept fixed.
In order to achieve the object, an electrode forming apparatus for electric parts includes: a tape having holding holes for holding board-shaped electric parts at regular intervals along a length thereof; a driving mechanism for feeding the tape in the direction of the length thereof; and a pasting unit for applying electric conductive paste to the board-shaped electric parts held by the holding holes of the tape fed by the driving mechanism, in order to form a electrode. In the case, each of the holding holes has a pair of opposite abutting edges for abutting on both opposite surfaces of the board-shaped electric parts, and at least one cutout portion formed in one of the abutting edges.
According to this invention, the board-shaped electric parts can be held by the pair of abutting edges. Thus, the electric parts can be conveyed with their attitude kept fixed regardless of adverse influences such as vibrations from the moving tape. Therefore, the electric conductive paste can be applied to predetermined areas of the electric parts more accurately without removing the electric parts from the conveying tape.
The pasting unit may have a pasting wheel that has an elastic cylindrical surface and a groove provided in the cylindrical surface. In the case, the cylindrical surface of the pasting wheel may be adapted to be deformed by the board-shaped electric parts held by the holding holes of the tape fed by the driving mechanism.
Preferably, a feeding speed of the tape and a moving speed of the cylindrical surface may be substantially identical with each other at least while the cylindrical surface is contact with the board-shaped electric parts held by the holding holes of the tape fed by the driving mechanism.
The pasting wheel may rotate continuously at a substantially constant speed. Alternatively, the pasting wheel may rotate intermittently.
The pasting wheel may have a plurality of parallel grooves provided in the cylindrical surface.
Preferably, the pasting unit may have a pair of pasting wheels. In the case, each of the pair of pasting wheels may have an elastic cylindrical surface and a groove provided in the cylindrical surface. In addition, the pair of pasting wheels may be arranged in such a manner that the cylindrical surfaces of the pasting wheels can sandwich the board-shaped electric parts held by the holding holes of the tape fed by the driving mechanism. In addition, each of cylindrical surfaces of the pasting wheels may be adapted to be deformed by the board-shaped electric parts held by the holding holes of the tape fed by the driving mechanism.
Preferably, a feeding speed of the tape and respective moving speeds of the cylindrical surfaces of the pair of pasting wheels may be substantially identical at least while the cylindrical surfaces are contact with the board-shaped electric parts held by the holding holes of the tape fed by the driving mechanism.
The pair of pasting wheels may rotate continuously at a substantially constant speed. Alternatively, the pair of pasting wheels may rotate intermittently.
Each of the pasting wheels may have a plurality of parallel grooves provided in the cylindrical surface.
For example, the tape is made of paper.
Preferably, the pair of abutting edges are parallel with each other.
Preferably, the cutout portion is formed in a central portion of each of the abutting edges so that each of the holding holes is cross-shaped.
Alternatively, the cutout portion may be formed in an end portion of each of the abutting edges so that each of the holding holes is T-shaped.
Preferably, the tape has feeding holes at regular intervals along the length thereof and the driving mechanism has engaging means for engaging the feeding holes for feeding operation.
Preferably, a drying unit is provided for drying the electric conductive paste applied to the board-shaped electric parts by the pasting unit.